U.S. patent application number 17/103570 was filed with the patent office on 2021-05-27 for artificial right atrium design for failing fontans.
This patent application is currently assigned to CHILDREN'S HOSPITAL LOS ANGELES. The applicant listed for this patent is CHILDREN'S HOSPITAL LOS ANGELES. Invention is credited to Sarah BADRAN, Cynthia S. HERRINGTON, Jon David MENTEER, Niema M PAHLEVAN, Heng WEI.
Application Number | 20210154385 17/103570 |
Document ID | / |
Family ID | 1000005288017 |
Filed Date | 2021-05-27 |
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United States Patent
Application |
20210154385 |
Kind Code |
A1 |
HERRINGTON; Cynthia S. ; et
al. |
May 27, 2021 |
ARTIFICIAL RIGHT ATRIUM DESIGN FOR FAILING FONTANS
Abstract
An artificial chamber including a first conduit, a second
conduit, a third conduit, and a wall defining a space; in which the
first conduit and the second conduit are positioned opposite one
another; in which the third conduit is opposite the wall; and in
which the wall has a concave surface is disclosed. The chamber can
be part of a system for providing pulmonary support. The system
includes the chamber and a first pump connected to the third
conduit, and connected to a fourth conduit; in which the chamber
receives fluid via the first conduit and the second conduit, in
which the first pump receives fluid from the chamber via the third
conduit; and in which the fourth conduit transports fluid from the
first pump to a first blood vessel. Methods of making a chamber and
a system, and methods of using the chamber and system are also
disclosed.
Inventors: |
HERRINGTON; Cynthia S.;
(Pasadena, CA) ; MENTEER; Jon David; (Calabasas,
CA) ; BADRAN; Sarah; (Rolling Hills Estates, CA)
; WEI; Heng; (Los Angeles, CA) ; PAHLEVAN; Niema
M; (La Canada, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
CHILDREN'S HOSPITAL LOS ANGELES |
Los Angeles |
CA |
US |
|
|
Assignee: |
CHILDREN'S HOSPITAL LOS
ANGELES
Los Angeles
CA
|
Family ID: |
1000005288017 |
Appl. No.: |
17/103570 |
Filed: |
November 24, 2020 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
62939992 |
Nov 25, 2019 |
|
|
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61M 2205/02 20130101;
A61M 2210/125 20130101; A61M 60/258 20210101; A61M 60/50
20210101 |
International
Class: |
A61M 1/10 20060101
A61M001/10 |
Claims
1. An artificial chamber, comprising: a first conduit, a second
conduit, a third conduit, and a wall defining a space; wherein the
first conduit and the second conduit are positioned opposite one
another; wherein the third conduit is opposite the wall; and
wherein the wall has a concave surface.
2. A system for providing pulmonary support comprising: a chamber
defined by a first conduit, a second conduit, a third conduit, and
a wall; and a first pump connected to the third conduit, and
connected to a fourth conduit; wherein the chamber receives fluid
via the first conduit and the second conduit 16, wherein the first
pump receives fluid from the chamber via the third conduit; and
wherein the fourth conduit transports fluid from the first pump to
a first blood vessel.
3. The system of claim 2, further comprising: a second pump
connected to a fifth conduit, and connected to a sixth conduit;
wherein the fifth conduit transports fluid from a second blood
vessel to the second pump; and wherein the sixth conduit transports
fluid from the second pump to a tissue.
4. The system of claim 2, wherein the wall has a concave
surface.
5. The system of claim 2, wherein the chamber includes a convex
surface and the wall has a concave surface.
6. The system of claim 5, wherein a ratio of a width of the convex
surface to the concave surface is from about 0.0:4 to about
4:0.0.
7. The system of claim 2, wherein the chamber has a volume of from
about 0.1 cc to about 150 cc.
8. The system of claim 2, wherein the chamber includes at least one
convex surface.
9. The system of claim 2, wherein the chamber is made of a material
that withstands a pressure of from about 0 mm Hg to about 10 mm
Hg.
10. The system of claim 2, wherein the chamber expands from about
5% to about 95% in volume relative to an original size of the
chamber.
11. The system of claim 2, wherein the chamber is made of a
material chosen from polyester, polytetrafluoroethylene, and a
combination thereof.
12. The system of claim 2, wherein the chamber includes an interior
surface with a coating.
13. The system of claim 2, wherein each of the first conduit, the
second conduit, and the third conduit includes at least one
valve.
14. The system of claim 2, wherein each of the first pump and the
second pump is one of a pressure-source pump and a flow-source
pump.
15. A method for using a system for providing pulmonary support in
a patient in need thereof, comprising: attaching the system to at
least one blood vessel, wherein the system includes a chamber
defined by a first conduit, a second conduit, a third conduit, and
a wall; and a first pump connected to the third conduit, and
connected to a fourth conduit.
16. The method of claim 15, further comprising attaching the first
conduit to a third blood vessel.
17. The method of claim 15, further comprising attaching the second
conduit to a fourth blood vessel.
18. The method of claim 15, further comprising attaching the fourth
conduit to a first blood vessel.
19. A method of making a chamber for a patient in need thereof,
comprising: imaging the patient to obtain measurements; determining
a long axis plane for the chamber; and making the chamber.
20. The method of claim 19, wherein determining the long axis plane
includes using computational fluid dynamic tools to minimize
particle residence time based upon the patient's measurements
obtained from the imaging.
Description
RELATED APPLICATION
[0001] The present application claims priority to U.S. Provisional
Application No. 62/939,992, filed Nov. 25, 2019, the entire
disclosure of which is hereby incorporated by reference.
FIELD OF THE INVENTION
[0002] The present invention relates generally to the field of
cardiac medical devices and systems. In particular, the invention
relates to a method and device to develop a new assist device for
Fontan patients by creating a chamber, such as a synthetic right
atrium, that minimizes blood particle component residence time,
thereby preventing blood clotting and avoids and/or prevents
over-pressurizing superior vena cava and inferior vena cava.
BACKGROUND OF THE INVENTION
[0003] The Fontan or Fontan/Kreutzer procedure is a palliative (not
curative) surgical procedure used to ameliorate complex congenital
heart defects, for example in young children. Exemplary heart
defects addressed by the Fontan procedure include heart valve
defects (tricuspid atresia, pulmonary atresia), abnormalities in
pumping ability of the heart (hypoplastic left heart syndrome,
hypoplastic right heart syndrome), and other complex congenital
heart diseases where a bi-ventricular repair is not possible or
contra-indicated (double inlet left ventricle, heterotaxy defects,
double outlet right ventricle, etc.).
[0004] In the Fontan procedure, a surgically created junction is
provided between the superior and inferior vena cava and the
pulmonary artery (PA), and venous blood flow is diverted from the
superior and inferior vena cava directly to the PA, bypassing the
right ventricle of the heart. Following the procedure, oxygen-poor
blood from the upper and lower body flows through the lungs without
being pumped by the heart. In this manner, the blood flow into the
lungs is driven only by central venous blood pressure. This
corrects hypoxia, and leaves a single heart ventricle responsible
for supplying blood to the body.
[0005] However, disadvantages and post-surgical complications are
associated with the Fontan procedure. In the short term, pleural
effusions (fluid build-up around the lungs) occur, requiring
additional surgical interventions. In the long term, atrial
scarring is associated with atrial flutter and atrial fibrillation,
also requiring additional surgical intervention. Other long-term
risks are associated with the procedure, such as protein-losing
enteropathy and chronic renal insufficiency, although these latter
risks are not yet fully quantified.
[0006] It is noted that a high central venous pressure is required
to provide a satisfactory supply of blood to the lungs after the
Fontan procedure. Immediately or even 2-5 years following the
procedure, it is known that the surgically created Fontan
circulation often fails due to that high venous pressure required
to drive pulmonary circulation. Long term mortality following the
Fontan procedure can be as high as 29.1%, characterized by
catastrophic failure of circulation and death. The expected
event-free survival rate following the Fontan procedure at one,
ten, and twenty-five years following the procedure is 80.1%, 74.8%,
and 53.6%, respectively. In early post-operative cases of failing
Fontan circulation, the Fontan connection must be surgically taken
down. In later post-operative cases, often the only remedy is heart
transplantation.
[0007] In many post-operative cases, the patient's heart is in such
a deteriorating state heart transplantation is not possible. In
many cases, the surgeons have reversed the Fontan to create a right
atrium to cannulate, but this results in massive bleeding, a poor
chamber for cannulation, and the inability to support the
patient.
[0008] What is needed is a system to ameliorate and/or treat at
least one of the health problems discussed above in a patient in
need thereof. For example, a system for providing pulmonary support
to a patient can be provided.
SUMMARY OF THE INVENTION
[0009] In an aspect, there is disclosed an artificial chamber
including a first conduit, a second conduit, a third conduit, and a
wall defining a space; in which the first conduit and the second
conduit are positioned opposite one another; in which the third
conduit is opposite the wall; and in which the wall has a concave
surface.
[0010] In another aspect, there is disclosed a system for providing
pulmonary support comprising: a chamber defined by a first conduit,
a second conduit, a third conduit, and a wall; and a first pump
connected to the third conduit, and connected to a fourth conduit;
wherein the chamber receives fluid via the first conduit and the
second conduit, wherein the first pump receives fluid from the
chamber via the third conduit; and wherein the fourth conduit
transports fluid from the first pump to a first blood vessel.
[0011] In a further aspect, there is disclosed a method for using a
system for providing pulmonary support in a patient in need
thereof, comprising: attaching the system to at least one blood
vessel, wherein the system includes a chamber defined by a first
conduit, a second conduit, a third conduit, and a wall; and a first
pump connected to the third conduit, and connected to a fourth
conduit.
[0012] Additional features and advantages of various embodiments
will be set forth, in part, in the description that follows, and
will, in part, be apparent from the description, or may be learned
by the practice of various embodiments. The objectives and other
advantages of various embodiments will be realized and attained by
means of the elements and combinations particularly pointed out in
the description herein.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] The present disclosure in its several aspects and
embodiments can be more fully understood from the detailed
description and the accompanying drawings, wherein:
[0014] FIG. 1 is a drawing of a system, according to an example of
the present disclosure;
[0015] FIGS. 2A-G are two-dimensional drawings of a chamber,
according to an example of the present disclosure;
[0016] FIGS. 3A-F are three-dimensional drawings of the chambers in
FIGS. 2A-F, respectively;
[0017] FIG. 4 is a hydraulic circuit set-up to simulate the use of
a system, according to an example of the present disclosure;
[0018] FIGS. 5A-J illustrate different experimental setup to
illustrate the effects of using different types of chambers and
pumps;
[0019] FIGS. 6A-J illustrate the pressures at the first conduit and
the second conduit corresponding to each experimental setup of
FIGS. 5A-J, according to an example of the present disclosure;
and
[0020] FIGS. 7A-F illustrate the simulated flow results
corresponding to each of the FIGS. 2A-F and 3A-F, according to an
example of the present disclosure.
[0021] Throughout this specification and figures like reference
numbers identify like elements.
DETAILED DESCRIPTION OF THE INVENTION
[0022] It is to be understood that both the foregoing general
description and the following detailed description are exemplary
and explanatory only, and are intended to provide an explanation of
various embodiments of the present teachings.
[0023] The present invention is directed to a system for providing
pulmonary support to a patient in need thereof. The patient in need
thereof can be failing from a prior Fontans procedure. In
particular, the patient can be exhibiting at least one health
problem chosen from pleural effusions, atrial scarring, atrial
flutter, atrial fibrillation, protein-losing enteropathy, chronic
renal insufficiency, and high central venous pressure. The system
can stabilize a patient with a failing Fontans procedure by
ameliorating and/or treating at least one of the health problems
discussed above. The system can preserve compliance, i.e., prevent
over-pressurizing blood vessels; and/or minimize particle residence
time thereby preventing or reducing the likelihood of blood
clots.
[0024] FIG. 1 illustrates a system 10 that can be surgically
implanted into a patient in need thereof. The system includes a
chamber 20 defined by a first conduit 14, a second conduit 16, a
third conduit 18, and a wall 11; and a first pump 22 connected to
the third conduit 18, and connected to a fourth conduit 28. The
chamber 20 can receive fluid via the first conduit 14 and the
second conduit 16. The first pump 22 can receive fluid from the
chamber 20 via the third conduit 18. In an aspect, the first pump
22 can include an additional conduit so that the third conduit 18
connects to the additional conduit of the first pump 22. For
example, the additional conduit can have an end that is smaller in
diameter than a diameter of the third conduit so that the end of
the additional conduit can fit within an end of the third conduit,
as shown in FIG. 1. The fourth conduit 28 can transport fluid from
the first pump 22 to a first blood vessel 26.
[0025] The system 10 can further include a second pump 30 connected
to a fifth conduit 34, and connected to a sixth conduit 32. The
fifth conduit 34 can transport fluid from a second blood vessel 38
to the second pump 30. The sixth conduit 32 can transport fluid
from the second pump 22 to an organ 36.
[0026] The conduits (e.g., first, second, third, etc.) of the
system 10 can transport a fluid between two members (e.g., chamber
20, and first pump 22) and/or a member (e.g., second pump 30) and a
tissue, such as a blood vessel (e.g., first, second, third, etc.).
The fluid can be blood. The conduits are numbered "first",
"second", "third", etc. for ease of reference and it is not
intended to limit the scope thereof. Each conduit 14, 16, 18, 28,
34, and 32 can include a first end and a second end. Each conduit
14, 16, 18, 28, 34, and 32 can include at least one valve located
at the first end and/or the second end. As an example, the first
conduit 14 can include a first end connected to the chamber 20,
wherein the first end includes a valve (not shown), and the second
end does not include a valve. As another example, the third conduit
18 can include a first end connected to the chamber 20 and
including a first valve, and can include a second end connected to
the first pump 22 and including second valve. In an aspect, each of
the first conduit 14, the second conduit 16, and the third conduit
18 includes at least one valve. For example, each of the first
conduit 14, the second conduit 16, and the third conduit 18 each
have a first end including a valve.
[0027] The first conduit 14 can transport a fluid, such as blood,
from a third blood vessel 15, such as a superior vena cava (SVC) 15
to the chamber 20. The second conduit 16 can transport a fluid,
such as blood, from a fourth blood vessel 17, such as an inferior
vena cava (IVC) 17. A blood vessel can be any vessel through which
blood circulates. Non-limiting examples of blood vessels include
artery, vein, capillary, arteriole, and venule.
[0028] The conduits 14, 16, 18, 28, 34, and 32 can be any size or
shape to transport fluid. The conduits 14, 16, 18, 28, 34, and 32
can have a diameter, such as an inner diameter, that matches or
substantially matches with a blood vessel, and/or an artificial
implant. Each conduit 14, 16, 18, 28, 34, and 32 can have the same
or different diameter, such as a diameter ranging from about 1.5 mm
to about 35 mm, for example, from about 1.9 mm to about 24 mm, and
as a further example, from about 2.1 mm to about 20 mm, including
all points in between the ranges. Each of the first conduit 14, the
second conduit 16, and the third conduit 18 can have the same
diameter "D".
[0029] As discussed above, each conduit 14, 16, 18, 28, 34, and 32
can include a first end and a second end. The diameter of each
conduit can be the same from the first end to the second end. The
diameter of each end of the conduit can be different. For example,
the diameter can increase or decrease along a length of the conduit
so that the first end and the second end are different.
[0030] Each conduit 14, 16, 18, 28, 34, and 32 can include a length
from the first end to the second end. The length of each conduit
14, 16, 18, 28, 34, and 32 can be the same or different. Prior to
insertion of the chamber 20 into a patient in need thereof, the
length of each conduit can have an initial length. The initial
length of each conduit can be shortened during insertion of the
chamber.
[0031] In an aspect, a chamber 20 including the first, second, and
third conduits can have standard sizes for each component. The
standard sizes can be designed based upon a imaging data from
patients. For example, patients age 2 years old could use a chamber
20 having first, second, and third conduits having a first standard
size; and patients age 4 years old could use a chamber 20 having
first, second, and third conduits having a second standard size. It
is envisioned that some patients may not "fit" standard sizes and
would require a custom-made chamber 20. A process for designing a
chamber 20 is discussed more fully below.
[0032] In an example, the conduits 14, 16, 18, 28, 34, and 32 can
be made of the same material as the chamber 20. In another example,
the conduits 14, 16, 18, 28, 34, and 32 can be made of a different
material from the chamber 20. Additionally, the conduits 14, 16,
18, 28, 34, and 32 can be made of the same material or can be made
from a different material. For example, conduits 14, 16 can be the
same material as conduit 18. As another example, conduits 14, 16
can be a different material from conduit 18.
[0033] The chamber 20 can be any size or shape to receive fluid. In
an aspect, the chamber can be configured to mimic a right atrium of
a heart.
[0034] The chamber 20 can be formed of any material. In an example,
the chamber 20 can be made of a rigid material. In another example,
the chamber 20 can be made of non-rigid (i.e., compliant) material.
The chamber 20 can be made of a material that can withstand a
pressure of from about 0 mm Hg to about 10 mm Hg, such as a
pressure of from about 1 mm Hg to about 9 mm Hg, and for example,
from about 2 mm Hg to about 8 mm Hg. Non-limiting examples of
suitable materials include polyester, polytetrafluoroethylene,
silicon, latex, any deformable FDA-approved biocompatible material,
and a combination thereof. Moreover, the chamber 20 can be made of
a material that can expand or contract (in volume) to about 5% to
about 95%, such as from about 10% to about 90%, and as an example,
from about 20% to about 85%, relative to an original size of the
material.
[0035] The chamber 20 can include a coating on an exterior surface
and/or an interior surface of the chamber 20. Such a coating can
include an antibiotic coating or an anti-coagulant coating. The
coating can include any drug-eluting material and/or matrix, for
example, to facilitate the release a drug into a patient in need
thereof. The drug can be any drug that does interfere with the
operation of the chamber 20.
[0036] The chamber 20 can also include at least one external ring.
For example, a first conduit 14 can include an external ring on at
least one of the first end and the second end. The external ring
can provide support. The external ring can prevent or inhibit
external compression and distortion of each conduit and/or the
chamber 20.
[0037] FIGS. 2A-G and FIGS. 3A-F illustrate a few exemplary shapes
of chamber 20. FIGS. 2A-F illustrate a chamber with two-dimensional
modeling, and FIGS. 3A-F illustrate the same chambers with
three-dimensional modeling, respectively. As shown, in FIGS. 2A-G
the chamber 20 can be defined by the first conduit 14, the second
conduit 16, the third conduit 18, and a wall 11. In an aspect, the
first conduit 14 can be oppositely-oriented with respect to the
second conduit 16. In another aspect, the third conduit 18 can be
oppositely-oriented with respect to the wall 11. The chamber 20 can
be configured to preserve compliance, such as by preventing
over-pressurizing from the first conduit 14 and the second conduit
16. The chamber 20 can also be configured to minimize particle
residency time, which can reduce and/or prevent blood clotting.
[0038] With regard to FIGS. 2A-G and FIGS. 3A-F, the first conduit
14, the second conduit 16, and the third conduit 18 have the same
diameter D. It should be noted that the diameter D of each conduit
can be the same or different.
[0039] As shown in FIG. 2G, the simplest shape of the chamber 20
can include the first conduit 14, the second conduit 16, and the
third conduit 18 each having the same diameter D, so that the
chamber has a width that is also D. The chamber 20 is defined by
the conduits 14, 16, 18, and is illustrated by the dashed line in
FIG. 2G. The third conduit 18 can be orthogonal to the first
conduit 14 and the second conduit 16 to form a T-shaped chamber 20,
with the wall 11 as a linear extension of the first conduit 14 and
the second conduit 16. FIG. 2G illustrates a baseline size and
shape from which the chamber 20 can be configured. As explained in
more detail below, the size and shape of the chamber 20 can be
altered by increasing or decreasing the wall 11 and/or the
connection surface of the third conduit 18 from an axis 13 to
provide a convex or concave surface.
[0040] In an aspect, the wall 11 of the chamber 20 can be increased
or decreased a predetermined width relative to the diameter D of
the first conduit 14 and/or the second conduit 16. In this manner,
the wall 11 of the chamber 20 can have a convex surface or a
concave surface. For example, as shown in FIGS. 2A and C, the wall
11 can be increased a width that is the same as the diameter D of
the conduits 14, 16 so that the wall 11 has a convex surface. As
another example, the wall 11 can be increased by a different width
relative to the diameter D of the first conduit 14 and the second
conduit 16 to provide a convex surface, such as 2D, as shown in
FIG. 2D. In an aspect, the wall 11 can have a convex surface that
is increased about 0.1D to about 4D, for example, from about 0.25D
to about 3.5 D, and as a further example, from about D to about 3D,
relative to an initial diameter D of the first conduit 14 and the
second conduit 16. It should be understood that 4D means 4 times
the diameter D of the first conduit 14 when each conduit of the
chamber 20 has the same diameter D. As discussed herein, the
chamber 20 can have a standard size or can be custom designed.
[0041] In another aspect, as shown in FIGS. 2B, E, and F the wall
11 can be decreased a width relative to the diameter D of the
conduits 14, 16 so that the wall 11 has a concave surface. For
example, the wall 11 can be decreased a width that is the same as
the diameter D of the conduits 14, 16 so that the wall 11 has a
convex surface, as shown in FIGS. 2B and E. As another example, the
wall 11 can be decreased to any a different width relative to the
diameter D of the first conduit 14 and the second conduit 16 to
provide a concave surface, such as 0.5D, as shown in FIG. 2F. In an
aspect, the wall 11 can have a concave surface that is decreased
about 0.1D to about 4D, for example, from about 0.25D to about 3.5
D, and as a further example, from about D to about 3D, relative to
an initial diameter D of the first conduit 14.
[0042] Referring back to FIG. 2G, the third conduit 18 can be
positioned orthogonal to the first conduit 14 and the second
conduit 16. See, e.g., FIGS. 2C and D. In another aspect, the third
conduit 18 can be positioned on a convex surface, as shown in FIGS.
2A, B, E, and F, opposite wall 11. For example, the third conduit
18 can be positioned at an apex of the convex surface. The third
conduit 18 can be positioned on a convex surface, opposite wall 11,
in which the convex surface is formed by an increased width
relative to the diameter D of the first conduit 14 and/or the
second conduit 16. For example, the third conduit 18 can be
positioned on the convex surface having a width the same as the
diameter D of the conduits 14, 16, as shown in FIGS. 2A and B. As
another example, the third conduit 18 can be positioned on a convex
surface that can be increased by a different width relative to the
diameter D of the first conduit 14 and the second conduit 16, such
as 2.5D, as shown in FIGS. 2E and F. In an aspect, the third
conduit 18 can be positioned on a convex surface that is increased
about 0.1D to about 4D, for example, from about 0.25D to about 3.5
D, and as a further example, from about D to about 3D, relative to
an initial diameter D of the first conduit 14 and the second
conduit 16. In an aspect, the chamber can include at least one
convex surface.
[0043] In an aspect, the chamber 20 can include a third conduit 18
positioned on a convex surface and a wall 11 having a concave
surface, as shown in FIGS. 2B, E, and F. In an example as shown in
FIGS. 2B and 3B, both the convex surface and the concave surface
can include the same width relative to the diameter D, which is the
same diameter as the diameter of the inlets 14, 16 and outlet 18.
In another example, as shown in FIG. 2E the convex surface can
include a width that is different than the diameter D the diameter
of the inlets 14, 16 and outlet 18, and the wall 11 can have a
concave surface with a width that is the same relative to the
diameter D. In yet another example, as shown in FIG. 2F, both the
third conduit 18 positioned on a convex surface and the concave
surface of wall 11 can include a different width relative to the
diameter D of the conduits 14, 16. For example, the third conduit
18 can be present on a convex surface that includes a width that is
about 2.5 times the diameter of the conduits 14, 16. Additionally,
the concave surface of wall 11 can include a width that is about
0.5 times the diameter of the conduits 14, 16.
[0044] The chamber 20 can include a convex surface and a concave
surface so that the shape of the chamber 20 mimics the shape of the
right atrium. A ratio of the width of the convex surface to the
concave surface can be from about 0.0:4 to about 4:0.0, such as
from about 0.5:3 to about 3:0.5. A volume of the chamber 20 can
include a volume from about 0.1 cc to about 150 cc, such as from
about 2 cc to about 100 cc, for example from about 5 cc to about 50
cc. The chamber 20 can have a standard volume based upon standard
sizes from a majority of patients sizes/ages. The chamber 20 can
also have a custom designed volume based upon a patient-specific
condition.
[0045] The first pump 22 and the second pump 30 can each be a
pressure-source pump (i.e., flow drops as resistance increases) or
a flow-source pump (i.e., flow does not drop with resistance
increases).
[0046] Fluid, such as reduced or low-oxygen blood (AKA blue blood),
from blood vessels 15, 17 can come together in chamber 20 via first
conduit 14 and second conduit 16. The first pump 22 can pump the
low-oxygen blood from the chamber 20 via third conduit 18 to a
blood vessel 26, which can transport the fluid to the lungs for
oxygenation.
[0047] In an example, if the left atrium and the left ventricle of
the organ 36 are functional, then, the organ 36 can pump oxygenated
fluid into the body via blood vessel 38. In another example, as
shown in FIG. 1, if the left atrium and/or the left ventricle are
not functioning properly, a second pump 30 can be utilized to pump
the oxygenated blood into the body. In this example, the second
pump 30 can include a conduit 32, which receives the oxygenated
blood through one of pulmonary veins, left atrium, and/or left
ventricle. The second pump 30 can then pump the oxygenated blood
into the blood vessel 38, such as the aorta, via the conduit
34.
[0048] There is disclosed a method for using a system for providing
pulmonary support in a patient in need thereof, comprising
attaching the system to at least one blood vessel, wherein the
system includes a chamber 20 defined by a first conduit 14, a
second conduit 16, a third conduit 18, and a wall 11; and a first
pump 22 connected to the third conduit 18, and connected to a
fourth conduit 28. The first conduit can be attached to a third
blood vessel 15. The second conduit 16 can be attached to a fourth
blood vessel 17. The fourth conduit 28 can be attached to a first
blood vessel 26. The method can also include attaching a second
pump 30. In particular, a sixth conduit 32 of the second pump 30
can be attached to an organ 36, such as the heart. Additionally, a
fifth conduit 34 of the second pump 30 can be attached to a second
blood vessel 28, such as an aorta.
[0049] There is also disclosed a method of making a chamber for a
patient in need thereof, comprising imaging the patient to obtain
measurements; determining a long axis plane for the chamber; and
making the chamber 20. The imaging can be any three-dimensional
and/or two-dimensional imaging of the patient. The step of
determining a long axis plane can be determined using computational
fluid dynamic (CFD) tools. The long axis plane is a cross-section
with two flow inputs, for example, the first and second conduits
14, 16; and at least one output flow, for example, the third
conduit 18. The long axis plane should minimize particle residence
time (PRT) based upon a patient's anatomical data obtained from the
imaging.
[0050] Using an appropriate material, such as a biocompatible
material, a chamber 20 can be made. A patient-specific
three-dimensional geometry of the chamber 20 can be created with
the determined long axis plane. The chamber 20 can fit the
patient's geometry and can preserve compliance using the blood
vessel diameters of the patient and physiological data (e.g.,
volume flow rates). The chamber 20 can be made using
three-dimensional printing and/or any known method for fabricating
a medical implant.
[0051] The method can further include testing hemodynamic responses
of the chamber 20. Non-limiting examples of hemodynamic responses
include pressure, flow, collapse. The testing can be performed in
physiologically accurate in-vitro systems.
[0052] The method can further include making a chamber 20 with a
mechanical material property, such as elasticity, viscoelasticity)
and three-dimensional geometry using an FDA-approved biocompatible
material.
[0053] The chamber 20 can be surgically implanted into the
patient.
EXAMPLES
[0054] FIG. 4 is an example of a hydraulic circuit used to evaluate
the compliance and particle resident time of an exemplary system
10. The chamber 20 was designed to function as an artificial right
atrium and is represented by the square in the center of the
set-up. The first conduit 14 and the second conduit 16 are
illustrated as the two inlet flows into the chamber 20. The third
conduit 18 (not shown) is an outlet flow from the chamber 20 to the
first pump 22, which then goes to the first blood vessel 26 and the
lung (labeled as "closed tank"). A syringe was used to add
compliance (S.C.)" to the system 10 at various locations. Systemic
the rest of circulatory circuit after the lung was simplified and
simulated with a tube and resistance. Fluid flow was measured (Q)
before the fluid entered the venous reservoir. Pressure was
measured (P.M.) at various location in the circuits such as first
conduit 14, second conduit 16, and inside the chamber 20. Pressure
was measured using a Millar System, PCU-200 Dual Channel Pressure
Control Unit and Mikro-Cath.TM. Disposable Pressure Catheter. Fluid
Flow was measured using a Transonic Systems Inc. T208 volume flow
meter. The stagnation pressure was 7 mm Hg, the pulsatile mode was
60 bpm, and the cardiac output was fixed to be 2 L/min. Three
separate sets of experiments were run: (a) with a rigid chamber
with compliance (pressure source pump), Examples 1-6; (b) a piston
pump, Examples 7-8; and (c) with a compliant chamber, Examples
9-10.
[0055] With regard to Examples 1-6 below, a rigid chamber with
added compliance was studied by using a syringe at the following
locations: chamber 20--0.1 ml/mmHg/kg; first conduit 14--0.08
ml/mmHg/kg; and second conduit 16--0.32 ml/mmHg/kg.
[0056] Example 1 (Comparative)--As shown in FIG. 5A, case 1 was a
system 10 including a chamber 20 with a first conduit 14, a second
conduit 16, and a third conduit 16 (orthogonal to the conduits 14,
16) that was directly linked to the lung. From the lung, the fluid
flow continued to the first pump 22, which then returned the fluid
to the venous reservoir and then back to the chamber 20. The
chamber 20 is a rigid chamber made of glass.
[0057] Example 2--As shown in FIG. 5B, case 2 was a system 10
including a chamber 20 with a first conduit 14, a second conduit
16, and a third conduit 16 (orthogonal to the conduits 14, 16) that
was connected to the first pump 22. The first pump 22 then
circulated the blood into the lungs. The chamber 20 is a rigid
chamber made of glass.
[0058] Example 3--As shown in FIG. 5C, case 3 was a system 10
including a chamber 20 with a first conduit 14, a second conduit
16, and a third conduit 16 (y-connector to the conduits 14, 16).
The y-connector was used to simulate a chamber 20 having a wall 11
with a concave surface and the third conduit 16 positioned on a
convex surface. The first pump 22 then circulated the blood into
the lungs. The chamber 20 is a rigid chamber made of glass.
[0059] Example 4 (Comparative)--As shown in FIG. 5D, case 4 was a
system 10 in which the first conduit 14 and the second conduit 15
merged together before they entered the chamber 20, i.e., a single
inlet and a single outlet. The third conduit 18 exited the chamber
20 and connected to the first pump 22. The first pump 22 then
circulated the blood into the lungs. The chamber 20 is a rigid
chamber made of glass.
[0060] Example 5 (Comparative)--As shown in FIG. 5E, case 5 was
similar to case 4, but also included a syringe on each of the first
conduit 14 and the second conduit 16 to simulate additional
external compliance to the system 10. Case 5 included a
pressure-source pump. In a pressure-source pump, when the
vasculature resistance increases, the pressure generated by the
pump will remain the same, but the cardiac output will decrease.
The chamber 20 is a rigid chamber made of glass.
[0061] Example 6--As shown in FIG. 5F, case 6 was similar to case
2, but also included a syringe on each of the first conduit 14 and
the second conduit 16 to simulate additional external compliance to
the system 10.
[0062] Example 7 (Comparative)--As shown in FIG. 5G, case 7 is
similar to case 5 except that case 7 utilized a flow-source pump
(e.g. piston-pump). In a flow-source pump, when the vasculature
resistance increases, the cardiac output will remain unchanged and
the pressure will increase. The chamber 20 is a rigid chamber made
of glass.
[0063] Example 8--As shown in FIG. 5H, case 8 is similar to case 6
where the pump is a strictly a flow-source pump (e.g.
piston-pump).
[0064] Example 9 (Comparative)--As shown in FIG. 5I, case 9 is
similar to case 5 where the chamber 20 was composed of a non-rigid
material, such as silicon or latex.
[0065] Example 10 (Comparative)--As shown in FIG. 5J, case 10 is
similar to case 7 where the chamber is composed of a non-rigid
material, such as silicon or latex.
[0066] Results
[0067] FIGS. 6A-J show the first conduit (FC) 14 and the second
conduit (SC) 16 simulated pressure results of cases 1-10,
respectively. The FC mean, FC pulse pressure, SC mean, and SC pulse
pressure results are also shown in Table 1.
TABLE-US-00001 TABLE 1 Mean and pulse pressure results of cases
1-10 FC mean FC PP SC mean SC PP Cases (mmHg) (mmHg) (mmHg) (mmHg)
Case 1 5.97 0.94 6.07 0.87 Case 2 5.45 19.98 5.55 19.03 Case 3 5.48
22.01 5.66 21.88 Case 4 5.54 23.24 5.58 22.57 Case 5 5.68 17.85
5.43 13.32 Case 6 5.60 17.51 5.66 13.04 Case 7 4.78 91.99 4.63
73.68 Case 8 5.31 85.32 5.05 71.71 Case 9 6.01 4.26 5.94 3.13 Case
10 5.88 4.82 5.34 4.10
[0068] Computational fluid dynamic (CFD) tools, such as using
Lattice-Boltzmann (LB) method using equations 1-6, below, were
conducted on various geometries to find an optimal chamber 20 size.
The results indicate that the geometry of FIG. 2F produced the
lowest particle residence time while preserving the total volume
within chamber 20. FIGS. 7A-F shows samples of simulated flow
results corresponding to each of the FIGS. 2A-F and 3A-F. Table 2
demonstrates the particle residence time in various geometries. In
LB method, Bhatnagar-Gross-Krook (BGK) is described as:
f.sub.i(x+e.sub.i.DELTA.x,t+.DELTA.t)=f.sub.i(x,t)+.OMEGA..sub.i(x,t)
(eq.1)
Where, f.sub.i is the particle velocity distribution function.
.OMEGA. i = - 1 .tau. [ f i ( x , t ) - f i e q ( x , t ) ] , .tau.
= 3 .mu. .rho. .DELTA. t + 1 2 ( eq . 2 ) ##EQU00001##
.OMEGA..sub.i: the collision operator, .tau.: relaxation time .mu.:
viscosity.
.rho.=.SIGMA..sub.if.sub.i,.rho.u=.SIGMA..sub.if.sub.ie.sub.i
(eq.3)
Carreau-Yasuda model (blood):
.mu. = ( .mu. 0 - .mu. .infin. ) [ 1 + ( .lamda. .gamma. . ) a ] n
- 1 a + .mu. .infin. ( eq . 4 ) ##EQU00002##
The rate-of-strain tensor is defined as:
s .alpha. .beta. = 1 2 ( .differential. u .beta. .differential. x
.alpha. + .differential. u .alpha. .differential. x .beta. ) ( eq .
5 ) ##EQU00003##
The shear rate is defined as:
{dot over (.gamma.)}= {square root over
(2.SIGMA..sub..alpha.,.beta.S.sub..alpha..beta.S.sub..alpha..beta.)}
(eq.6)
TABLE-US-00002 TABLE 2 Average particle residence time in various
geometries FIG. 2 PRT.sub.ave (unitless) FIG. 3 PRT.sub.ave
(unitless) (a) 10.80 (a) 11.59 (b) 7.56 (b) 10.01 (c) 9.55 (c)
12.18 (d) 11.50 (d) 14.81 (e) 8.90 (e) 10.73 (f) 8.82 (f) 11.31
[0069] The description of the inventions herein in their many
embodiments is merely exemplary in nature and, thus, variations
that do not depart from the gist of the invention are intended to
be within the scope of the invention. Such variations are not to be
regarded as a departure from the spirit and scope of the
invention.
* * * * *